1. Barometers come in many forms. As weather forecasting instruments go, barometers predict rain or shine. Rising pressure usually indicates sunny skies, while falling pressure means a good chance of rain.
2. Two common types of barometric weather instruments are the mercury barometer and the aneroid barometer. Most of the ones here are aneroid barometers, because they do not use liquid to attain a reading.
3. Barometric pressure can be read in a number of ways by weather instruments. The most common of these is in inches of mercury (often transcribed to a dial or digital readout), or in millibars.
4. Digital barometers are perfect for going out into the field. Many digital barometers can retain readings over the previous day, and you can compare hourly readings, too.
5. When using your barometer as a forecasting weather instrument, you should know that the absolute reading at any given time is not the most important aspect. Rather, the rate of change.
